Fire verification systems are being developed for use in freight compartments of aircraft. Such systems, however, are not yet in actual practical use due to shortcomings and problems in the development thereof. Particularly, algorithms for automatically interpreting optically obtained information for determining whether a fire does or does not exist in the optically monitored space are not yet adequately developed to the required level of reliability. Furthermore, any such algorithms must still be tested for validity. Thus, it is estimated that optical fire verification systems will not be in actual use in aircraft freight compartments for the next two to six years, with respect to an automatic fire detection and verification by such a system. Instead, any such optical fire monitoring system would be expected to merely provide not much more than a video image of the freight compartment, whereby the pilots must then visually evaluate and interpret the obtained video image in order to determine or estimate whether or not there is a fire in the freight compartment. It is also essentially not possible with such conventional systems to precisely determine the location of a fire in the freight compartment. While the location of the fire can be visually estimated, the precision of such locating depends on the number of cameras being used in the system, and is thus very cost intensive. A further disadvantage of such known systems using CCD cameras is that only temperatures above about 300° C. can be visually detected and measured due to the wavelength dependence.
German Patent DE 39 17 205 C1 discloses a fire fighting apparatus for use in freight or cargo aircraft as well as passenger aircraft. This known apparatus comprises a fire extinguishing unit mounted on a carriage which is movably arranged along a rail extending longitudinally in the aircraft. Particularly, the fire extinguishing unit includes a fire extinguishing nozzle that is pivotably mounted on the carriage, and the carriage can be actively driven along the rail according to remote control commands from the cockpit of the aircraft. A video camera is coupled with the fire extinguishing unit such that the lens of the video camera monitors the area or space at which the fire extinguishing nozzle is directed. Thus, the pilot or other personnel in the aircraft can control the motion of the carriage along the rail, as well as the pivoting position of the fire extinguishing nozzle, and trigger the release of a fire extinguishing agent through the nozzle, while monitoring the area in front of the nozzle by means of a video image provided by the video camera. While such a system provides for the active combat and extinguishing of a fire in connection with video monitoring of an enclosed space, such a system is not suitable for detecting and locating an outbreak of a fire in the first place.